This invention relates to typewriters and similar machines and is particularly directed to a method for automatically underlining a text section whose characters can be stored in a memory, where the beginning of the text section to be underlined is marked by entering an underline command, and the underlining is performed by entry of an underline end command between the underlining beginning and ending marks.
One of the requirements an operator of a typewriter or similar machine must handle is underlining defined areas of a typed text without hindering in so doing a swift typing of characters, but where the underlining of a typed text section must not be postponed because the operator would otherwise be required to make a note of this area, return the printing head to the beginning position of this area, and manually type repeatedly underlining.
To meet this requirement it has been suggested, e.g., in U.S. Pat. No. 4,392,758, to automatically underline the respective text section upon entering two commands marking the beginning and end of the text section which is contained in between and must be underlined. For that purpose, the operator presses, during typing, a first command key at the beginning of the area to be underlined, continues typing at normal speed, and presses a second command key at the end of the area to be underlined. The characters entered (and/or codes representing these characters) are stored in a line memory and the two commands marking the section to be underlined are stored as special codes between the characters in typing sequence. Each of the typed characters and also the underline command codes are then stored in memory exactly in the sequence in which they will be printed on the paper by the printer of the machine.
Entering the second underline command at the end of the section to be underlined additionally causes the memory content to be searched in reverse direction until the beginning code for the underlining area is found among the stored characters. Next, every character located to the right of the code is automatically underlined until the ending code is found in memory. This solution presupposes a rigid order of the stored characters in the same way they appear on the paper. But the rigidity of such storing is often undesirable, among other things, because then it is necessary to occupy memory locations for any spacing steps, tabulating jumps, etc.
The problem underlying the invention is providing a method of the initially-mentioned type for underlining defined text sections where the typing speed of the operator of a machine so equipped is not impeded, but where no memory with fixed positional allocations is required.